Anonymous
(x+2)/(x+3) = (x-7)/(x+1)
Eliminate the fractions by multiplying by (x + 3)
x + 2 = (x + 3)(x - 7)/(x + 1)
and (x + 1)
(x +1) (x + 2) = (x + 3)(x - 7)
multiply out the brackets
x² + 3x + 2 = x² - 4x - 21
bring all the x values to the left of equal sign (remember,they change signs)
7x = -23
x = - 23/7
?
(x + 2)/(x + 3) = (x - 7)/(x + 1)
(x + 2)(x + 1) = (x + 3)(x - 7)
x^2 + 3x + 2 = x^2 - 4x - 21
7x = -23
x = -23/7
Jim
Personally, I prefer to phrase it "maintain equality"
Multiply both sides of equal sign by same amount (x+1) and (x+3)
Expand and collect terms, solve for 'x'
x = -23/7
David
If: (x+2)/(x+3) = (x-7)/(x+1)
Then: (x+2)(x+1) = (x+3)(x-7)
Multiply out the brackets: x^2 +3x +2 = x^2 -4x -21
Collecting like terms: 7x = -23
Divide both sides by 7: x = -23/7
Ian H
The cross multiplication part was simply
(x + 2)(x + 1) = (x - 7)(x + 3), observe that terms in x^2 cancel
3x + 2 = - 4x - 21.
x = -23/7